document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1170633>Question 1170633</A>: <I><SPAN STYLE=\"word-break: break-all;\"> At a school assembly there are 100 students in grade 9, 125 in grade 10, 225 in grade 11, and 170 in grade 12. Everyone at the assembly entered their name for a door prize. What is the probability that the prize will be won by,\r<BR>\n" );
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document.write( "a) a grade 11 or 12 student?\r<BR>\n" );
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document.write( "b) a grade 12 student, if all grade 11 students are disqualified from winning?\r<BR>\n" );
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document.write( "Thanks\r<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #795502 by </B><A HREF=/tutors/aboutme.mpl?userid=math_tutor2020><B>math_tutor2020(3817)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=math_tutor2020><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=795502\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <font color=black size=3><BR>\n" );
document.write( "Part (a)\r<BR>\n" );
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document.write( "There are 100+125+225+170 = 620 students total.\r<BR>\n" );
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document.write( "Of that total, 225+170 = 395 are in grades 11 or 12\r<BR>\n" );
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document.write( "Divide the values to get the fraction 395/620 = 79/124\r<BR>\n" );
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document.write( "Use your calculator to find that 79/124 = 0.6371\r<BR>\n" );
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document.write( "Exact Answer as a fraction = 79/124<BR>\n" );
document.write( "Approximate Answer in decimal form = 0.6371<BR>\n" );
document.write( "Approximate Answer in percent form = 63.71%\r<BR>\n" );
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document.write( "Part (b)\r<BR>\n" );
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document.write( "Subtract off the 225 grade 11 students who are disqualified\r<BR>\n" );
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document.write( "The total goes from 620 to 620-225 = 395\r<BR>\n" );
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document.write( "Or you could add up the other grades that aren't grade 11<BR>\n" );
document.write( "100+125+170 = 395\r<BR>\n" );
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document.write( "Divide the number of grade 12 students over the new total 395 to get 170/395 = 34/79 = 0.4304 = 43.04%\r<BR>\n" );
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document.write( "Exact Answer as a fraction = 34/79<BR>\n" );
document.write( "Approximate Answer in decimal form = 0.4304<BR>\n" );
document.write( "Approximate Answer in percent form = 43.04%<BR>\n" );
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